2021 NBA Finals Preview
To me, the focus of these finals is Giannis Antetokounmpo. When will he come back? Does he play at all? If he does, is he 100%? If you knew the answers to these questions, you would probably know who the next NBA champion is. Sure, there are lots of moving parts. Khris Middleton has been cold-blooded, Chris Paul is hungry, and DeAndre Ayton is my current choice for the so-far playoffs MVP. But the story is this: with Giannis, the series is a near toss-up. Without him, the Suns are likely to win their team’s first NBA championship.
I can’t offer opinions on Giannis’ return timeline; unfortunately I don’t know a lot about knee ligaments. However, I will try to prepare you with championship odds depending on when he returns. Certainly, the Suns are favorites. But how big of favorites? At what point does Giannis need to return to make it a series? Let’s dig in.
Giannis’ Impact on the Bucks
There are many different ways of measuring an individual player’s impact on his team. Perhaps the most popular include NET rating, box plus/minus, and a player’s RAPTOR rating. Each of these statistics combines a player’s total performance into one, simple number. This number represents ‘how many points better your team is with this player on the court instead of an average player’.
If your rating is 8.0, then your team’s margin over the course of 100 possessions should be 8 points better than the margin if that player didn’t play. Giannis’ rating this season is about 6.3 points per 100 possessions – good for 5th best in the league.
Our end goal is to figure out how good Milwaukee is without Giannis. We’re going to combine our Ensemble Ratings for Milwaukee with Giannis’ RAPTOR rating to come to a final estimate for Milwaukee’s rating without Giannis. Our version of ensemble that weights the playoff games more heavily has Milwaukee at a 9.2. A good portion of that is Giannis’ credit. How much?
Milwaukee plays at a pace of 97 possessions per 48 minutes. Giannis RAPTOR value is 6.3 points per 100 possessions. Giannis averaged 33 minutes a game in the regular season. Putting all three of these together, we can estimate that Giannis is worth 4.2 of those 9.2 points. To put it another way, our best guess for how good Milwaukee is without Giannis is that they are 5 points better than a league-average team. For a direct comparison, that means that the Giannis-less Bucks are about as good as Portland. To me, that feels correct and so we’re going to run with it.
Giannis-Dependent Championship Probabilities
If Giannis plays every game (which we know he will not), the Suns win the series in about 60% of our simulations. Most of that advantage is due to having home court – if Milwaukee had home court, then they win the series about 51% of the time.
We simulated the series 10,000 times for each scenario: Giannis is back game 1, he comes back game 2, etc. In each case, we computed the probability that Phoenix wins the championship. The results are summarized in the table below.
Giannis Comes Back in…. | Phoenix Championship Probability |
Game 1 | 60% |
Game 2 | 64.3% |
Game 3 | 69.5% |
Game 4 | 74% |
Game 5 | 77.5% |
Game 6 | 81.7% |
Game 7 | 85% |
Never | 88% |
Roughly put, every game that Giannis misses decreases the Bucks championship probability by about 5 percentage points. The current thinking from a lot of the Milwaukee crowd is that Giannis comes back for game 3 in Milwaukee. This makes sense because it fits well with the timeline of typical hyper-extended knee injuries and it always makes more sense to wait to come play on your home court for your first game back.
There is always the possibility that he comes back in, say, Game 3 but is on a minutes restriction. In this case, the Bucks championship probability will be somewhat less than 30.5% but exactly how much less depends on the minutes played. The only things that are clear going into these NBA finals is (1) Phoenix is favored, (2) Milwaukee needs their two time MVP back as soon as possible, and (3) I’m going to regret staying up late to watch every single late-starting west coast game there is.
